COLTON - Calling teaching the nation's "most important work," Democratic presidential challenger John Kerry on Thursday unveiled a $30 billion, 10-year initiative to increase teacher pay while imposing stricter standards on instructors. The Massachusetts senator, on the second day of a two-day Southern California campaign swing, called for a "new bargain" for teachers and children that would recruit and retain 500,000 teachers over four years. "Children and schools together have been abandoned by misplaced priorities," he told students, teachers and supporters at San Bernardino County's Colton High School. "And teachers, the front-line troops in too many battlegrounds in our country,...